Multi-stage forming machine

ABSTRACT

A machine for cold forming workpieces in which workpieces are subjected to a sequence of work operations performed by a bank of co-operating tools and dies, therebeing transfer means for transferring each workpiece through successive work stations in the bank so as to be subjected sequentially to the action of successive co-operating tools and dies. The machine has two such banks operating 180* out of phase and the transfer means of both banks are carried by a common reciprocable slide, the arrangement being such that, in one direction of its reciprocating movement, the common slide moves the transfer means of one bank in a direction which advances the workpieces in that bank to successive work stations while the transfer means of the other bank are returning, and, in the other direction of reciprocating movement of the slide, the transfer means of the other bank advance the workpieces in the other bank while those of the one bank return.

United States Patent [151 3,695,088

Alvi'et a1. 1 Oct. 3, 1972 [54] MULTI-STAGE FORll/IING MACHINE 3,460,7358/1969 AkiraShibata ..72/335 [72] Inventors gs gz g j i z l PrimaryExammerCharles W. Lanham Frederick summerfin Harper; AssistantExaminer-Gene P. Crosby den an of England Attorny-Kemon, Palmer &Estabrook [73] Assignee: Aerpat A.G.,Zug, Switzerland [57] ABSTRACT 4[22] Filed: Aug. 5, 1970 A machine for cold forming workpieces in whichworkpieces are subjected to a sequence of work [21] Appl' 6l070operations performed by a bank of.'co-operating tools and dies,therebeing transfer means for transferring [30] Foreign ApplicationPriority Data each workpiece through successive work stations in I thebank so as to be subjected sequentially to the acl51969 Great tion ofsuccessive co-operating tools and dies. The machine has two such banksoperating 180 out of fits-(glphase a d the transfer means f b th banksare cap I I I a common reciprocable Slide the arrangement 8 ?fg z ggqgjggf i 3 being such that, in one direction of its reciprocating Imovement, the common slide moves the transfer R f Ct d means of one bankin a direction which advances the [56] e erences e workpieces in thatbank to successive work stations UNITED STATESv PATENTS while thetransfer means of the other bank are retuming, and, in the otherdirection of reciprocating move- 3 3 2/ 1968 Brfldlee "72/335 ment ofthe slide, the transfer means of the other bank 22,122 33 advance theworkpieces in the other bank while those 2. ms of the one b k return-2,279,417 4/1942 Stevens ..72/405 1,005,622 10/191 1 Eisenbeis ..72/4051 Claim, 11 Drawing Figures PATENTEnuma m2 3,695,088

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SHEET USUF 10 6 t forn iys PATENTED ET 3 I 72 SHEET U8UF 1O PATENTEDUET3 I972 SHEET 10 0F 10 1 MULTI-STAGE FORMING MACHINE The inventionrelates to a multi-stage forming machine of the type comprising:

a plurality of dies for receiving workpieces successively;

a plurality of toolholders each associated with one of the dies, eachfor holding a tool and each reciprocable to bring the tool to strike aworkpiece received in the associated die;

means for reciprocating the toolholders substantially in unison so thatthe tools are all withdrawn from the dies at least for a commonwithdrawal period in each reciprocation; and transfer means fortransferring workpieces successively from one die to the next duringeach common withdrawal period of the tools, the transfer meanscomprising workpiece-gripping means and a reciprocable transfer slide,reciprocation of the transfer slide in appropriate relationship to thereciprocation of the toolholders causing, during advance movement,advance of the workpiece-gripping means from one die to the next and,during return movement, return of the workpiece-gripping means from thesaid next die to the said one die. Such a-multi-stage forming machine ishereinafter referred to as a multi-Stage forming machine of the typedefined. Such machines, and their manner of operation, are well known tothose skilled in the art of manufacturing large numbers of small metalarticles, e.g. rivets.

The invention provides, in one of its aspects, a multistage formingmachine of the type defined, which machine comprises:

two banks each consisting of a plurality of dies and associatedtoolholders;

means for reciprocating thetoolholders of one bank substantially 180 outof phase with the toolholders of the second bank;

and a common reciprocable transfer slide for the transfer means of bothbanks;

the arrangement being such that when the common reciprocable transferslide is moving in one sense the workpiece-gripping means of the firstbank are advancing while the workpiece-gripping means of the second bankare returning, and when the common reciprocable transfer slide is movingin the opposite sense the workpiece-gripping means of the first bank arereturning while the workpiecegripping means of the second bank areadvancing.

The common reciprocable transfer slide may comprise a single member.However, in a preferred embodiment of the invention, it comprises twomembers, each associated with the workpiece-gripping means of one of thebanks, linked togetherfor movement in unison. Preferably the members arelinked together by an adjustable linkage which provides for relativeadjustment of the two members in the direction of their reciprocation.

.In a preferred embodiment of the invention, the two banks arepositioned relatively end-to-end in a straight line, and the machine isarranged so that workpieces in each bank are moved progressively towardsthe adjacent ends of the banks where there may be provided a commondischarge station for workpieces from both banks. In this case,workpieces are discharged at the discharge station from the two banksaltemately. Alternatively, separate adjacent discharge stations, one foreach bank, may be provided at the adjacent ends of the whereby afterbeing struck by the associated tool the workpiece can be fully ejectedfrom the die before being gripped by the workpiece-gripping means,

, without tending to tip sideways out of its vertical position.

A specific embodiment of the invention will now be described by way ofexample and with reference to the accompanying drawings, in which:

FIG. 1 is a front elevation of a multi-stage forming machine;

FIG. 2 is an elevation of one end of the machine;

FIG. 3 is an elevation of the other end of the machine (part beingomitted);

FIG. 4 is a plan view of the transfer means;

FIG. 5 is a diagrammatic section through the machine showing therelative positions of some cams;

FIG. 6 is a plan view, on the line VI VI of FIG. 5,

of the transfer slide reciprocating means;

FIGS. 7 and 8 are front elevations of the machine, partially simplified,illustrating the toolholders and transfer slide attwo positionsrespectively apart in their cycles of reciprocation; I

FIGS. 9 and 10 are sections (on the lines IX IX of FIG. 10 and X X ofFIG. 9 respectively) at right-angles to each other, showing part of thewire feed and thecropping means; and

FIG. 11 is a cross-section showing by way of illustration, a die andtool of one of the banks.

The twin bank multi-stage forming machine of this example has a generalarrangement which will be ap-' parent from FIGS. 1, 2, 3 and 4. It isbuilt in a strong frame 11 supported on a substantial base 12. The Themachine has two banks A and B adjacent each other in end-to-endrelationship, each bank occupying one half of the machine frame. The twobanks are substantially identical with each other, except that one issubstantially a mirror image of the other. Each bank comprises a slugcropping station, at which a slug is cropped from the end of a wire feedto form a workpiece, four workpiece forming stages through which theworkpiece passes successively, and a discharge station at which theworkpieces are discharged from the machine. In this example, there is asingle discharge station 13 which is common to both banks, positioned atthe junction between the banks in the center of the machine, and the twoslug cropping stages are positioned oneat the outer end of each bank.

Bank A comprises four dies DAI, DA2, DA3 and DA4, and bank B likewisecomprises four dies DB1, DB2, DB3 and DB4. (In FIG. :4, the dies arerepresented schematically, the actual construction of the die forming nopart of the present invention). The common discharge station 13 issituated midway between the two final dies DA4, DB4. The spacing betweeneach die and the next is the same for both banks, and is also the sameas the distance between each final stage die DA4, DB4 and the commondischarge station 13.

At the outer end of each bank A, B, is situated a cropping station CA,CB respectively, the positions of the center line of each beingindicated in FIG. 4. FIG. 4 also illustrates the transfer means. Thiscomprises workpiece-gripping means associated with each die, in the formof a pair of fingers. Associated with bank A are four pairs of fingersFAl, FA2, FA3 and FA4 and an arm 14A. Likewise, associated with bank Bare four pairs of fingers FBI, FB2, F83 and FB4 and an arm 14B.

The pairs of transfer fingers of both banks are carried toothed arms 27,28, each constituting part of a spur gear. Each closing camis elongatedin the direction of reciprocation of thetransfer slide so that thefollower roller 25 can be engaged by the cam face throughout the travelof the slide. When the cam is moved into the open position (as in bank Ain FIG. 4) it engages the roller 25 and causes the two arms to rotateabout their pivot to open the fingers. When the cam is in its closedposition (as in bank B in FIG. 4) the tension coil spring of each pairof arms closes the fingers. Movement of each finger closing cam FCAI,FCA2, FCA3, FCA4,

. FCBl, FCBZ, FCB3, FCB4 is actuated by an associated on a reciprocableslide 16, which comprises two separate members 16A and 16B rigidlyconnected together by' a linkage 17. The member 16A carries the set offour pairs of fingers and the arm 14A of bank A and the member 163carries the set of four pairs of fingers and the arm 14B of bank B. Thelinkage 17 can be adjusted to adjust the distance between the twomembers 16A and 16B in the direction of reciprocation of the slide 16,in order to correctly align the two sets of fingers and arms relativelyto each other. The arms 14A and 14B are fixed in position relative'tothe slide members 16A and 16B respectively and the fingers of each pairare movably mounted on the slide members so as to be capable of grippingand releasing workpieces.

When the machine is operating, the first pair of fingers FAl transfer acropped slug from the cropping station CA to the die DAl while thesecond pair of fingers FA2 transfer a workpiece from die DAl to die DA2,and so on. Workpieces from the two final dies DA4, DB4 are transferredto the discharge station 13 by means of-the fixed arms 14A, 148respectively. Each fixed arm has a circular workpiece receiving aperture15 near its end in which the workpiece is carried from the final stagedie to the discharge station. As the slide reciprocates, the apertures15 are moved between positions in which they are aligned alternatelywith the center of the final die and the discharge station.

The general construction and method of operation of the pairs oftransfer fingers used in this machine is well known to those skilled inthe art of multi-stage-progressive cold forming machines, and will onlybriefly be described here. Taking as an example the pair of fingers FA],these two fingers are each mounted at one end of an arm 18, 19respectively. Each arm is pivoted approximately mid way along its lengthon a pillar 21, 22 respectively. The other end of the two arms arejoined by means of a tension coil spring 23 which urges the two fingersFAl together. In FIG. 4, the fingers of bank B are shown in their closedposition and the fingers of bank A are shown open. Adjustable stops areprovided for adjusting the extent to which the fingers close on eachother to properly grasp the workpiece. The finger opening mechanism isillustrated in FIG. 4 with reference to the pair of fingers FA4. Securedto one finger of the pair is an arm 24 having at its remote end a camfollower roller 25 which engages with an elongated closing cam FCA4. Thetwo fingers are coupled together for opposing pivoting movement abouttheir respective pivots by means of interengaging rotating cam 30A or30B (for banks A and B respectively) on a camshaft 29 in the machine. Ingeneral, the finger closing cams of each bank move in synchronism, butminoradjustments in the phase of their relative movements are possible.

As illustrated in FIG. 1, the transfer slide 16 reciprocates in amachine slideway in the front lower cross member 31 of the machineframe. The mechanism causing its reciprocation will be described later.

Also as illustrated in FIG. 1, associated with each die in each bank isa toolholder which is reciprocable vertically to cause a tool mounted inthe lower end of the toolholder to strike the workpiece in theassociated die when the toolholder reaches the bottom of its stroke.Thus in bank A there are four toolholders TAl, TA2, TA3 and TA4 andlikewise in bank B, there are four toolholders TBl, TB2, TB3 and TB4.The design and operation of the particular tools secured to the bottomsof the toolholders of each bank is arranged so that each tool provides afurther stage in the forming of the workpiece as the workpieceprogresses from the slug cropping station to the discharge station butotherwise fonns no part of the present invention, and will not bedescribed further. In this machine, each toolholder is provided in thefonn of a vertically disposed ram reciprocable in suitable slidebearings in the frame middle cross member 32. Each toolholder isreciprocated by means of a pair of cams, one for raising the toolholderand one for lowering it. The four toolholders of bank A haverespectively four raising cams RCAl, RCA2, RCA3 and RCA4, and fourlowering cams LCAl, LCA2, LCA3 and LCA4. Likewise, the toolholders ofbank B have respectively four raising carns RCBl, RCB2, RCB3 and RCB4,and four lowering cams LCBl, LCB2, LCB3 and LCB4. A suitable separatefollower is provided for each raising and lowering cam respectively,secured to the upper part of the associated toolholder. All the raisingand lowering cams are mounted on the same main camshaft 33. The cams aregenerally arranged so that the four toolholders of one bank are raisedwhen the four toolholders of the other bank are lowered i.e. thereciprocation of the two banks of toolholders is substantially out ofphase. Each cam is suitably shaped for the function which it performs,and provision is made for minor adjustment of the phase of each cam inorder to permit the most efficient working of the machine.

Associated with each bank of the machine is means for feeding wire tothe cropping station of that bank.

The wire feed means associated with bank A will be described, thatassociated with bank B being similar. As shown in FIG. 2, a feed reel 35of wire stock is situated on the floor behind the machine, supported ina suitable stand 36. The wire 37 passes upwardly and over a guide pulley38 secured to the outer upper end of an arm 39 mounted on the upper partof the machine frame. The wire then passes forwardly and downwardly, andpasses vertically downward through two straighteners 40. Thestraightened wire then passes vertically downwards just inside the sideof the machine frame and behind the camshaft 33. While within themachine frame and adjacent the reciprocating toolholders' and camshaft,the wire passes through a tube 41 which protects it from contaminationby lubricating oil splashes. At the bottom end of the tube 41 the wireemerges into a feeding device and cropping means, which are shown inFIGS. 9 and 10.

The feeding device comprises two feed wheels 42 and 43 which touchtangentially to provide a nip, the peripheral face of each wheel havingin it a groove 44 of part circular cross-section to receive and grip thewire. These two feed wheels are geared together by means of gear wheels45 and 46 (only a few teeth of each gear wheel are illustrated in FIG.9) for rotation in unison in opposite directions to feed the wire stockdownwards through their nip. The feed wheels are rotated intermittentlyby means of a drive to the gear wheel 46, comprising a ratchet device 47driven by a connecting rod 48, the remote end of the rod 48 beingsecured ina slide 49 along a rockingarm 51. The rocking arm 51 pivotsabout a pin 52, and is oscillated by means of a follower arm 55 alsosecured to the pin 52 and spring urged into contact with a cam 54 on ashaft 55. The shaft 55 is rotated continuously in synchronism with theremainder of the machine. The length of wire fed at each revolution ofthe shaft 55 is determined by the position of the upper end of the rod48 along the slide 49 in the oscillating arm 51. The position of theupper end of the rod 48 relative to the slide 49 is adjustable so as tovary the angle through which the feed wheels 42 and 43 are advanced ateach revolution of the shaft 55 and so to adjust the length of wire fedat each revolution.

Below the feed wheels 42, 43 the wire 37 passes through a further shortlength 56 of protective tubing and then through a fixed cropping die 57formed of hardened steel. This cooperates with a similar movablehardened steel cropping die 58 carried in a cropping slide 59. Thecropping slide 59 is reciprocable between two positions, i.e. a rearwardposition (shown in FIG. 9 in solid lines) in which the-cropping dies 58and 57 are superposed, and a forward position (illustrated in FIG.

9 in broken lines and with reference numerals with the suffix a in whichthe movable cropping die 58 is in alignment with the center of the firststage fingers FAl. The cropping slide 59 is reciprocated by means of asuitable rocker mechanism which is actuated by a cam shaftdriven insynchronism with the remainder of the machine. When the cropping slide59 is in its rearward position with the movable cropping die 58 alignedwith the fixed cropping die 57, a length of wire is fed downwardlythrough the die 57 into the die 58 by the feed wheels 42, 43. Themaximum length of wire which can be fed into the movable cropping die 58is determined by a positive stop provided by the upper end of a pin 61underneath the die 58 within the slide 59. The lower end of the pin 61rests on and slides along the provided with ejectors, EAI, EA2, EA3 andEA4 upper face of abar 62, the height of which is adjustable by means ofa screw device 63-. Thus the length of wire cropped to provide a slug orbillet is accurately adjustable.

When the cropping slide 59 moves from its rearward position, the wirewithin the movable cropping die 58 is sheared from the stock at theinterface of the two dies 57, 58 to provide a slug. The slug issupported in the die 58 on the top end of the pin 61 and is carriedforward within the die 58 until the slide 59 reaches its forwardposition, indicated by numeral 590 and shown in broken lines in FIG. 9.This position is also shown (in full lines) in FIG. 10. When the slide59 reaches its forward position, the pin 61 is then immediately above anejector 64, the upper end of which passes through the block 62. Theejector 64 is then actuated (by means which will be described later) toeject the cropped-slug from the cropper die 58, so that it standsvertically upon the upper end of pin 61. The slug is then grasped by thefingers FAl and transferred to the die DAl of the first stage of bank A.

The four dies DAl, DA2, DA3 and DA4 are each respectively, which areindicated in FIG. 1 and also, in outline, in FIG. 10. Likewise the diesDB1, DB2, DB3

and DB4 of bank B have four ejectors EBl, EH2, BB3

and BB4. Each ejector is actuated by means of a .separate ejector cam,the lower end of each ejector resting on a rocker arm and the undersideof the rocker arm contacting the ejector cam. The eight rocker armsRA1,'RA2, RA3, RA4, RBI, RB2, RB3, RB4 and the eight ejector cams ECAl,ECA2, ECA3, ECA4, ECBl, ECB2, ECB3, ECB4 respectively are indicated inFIG. 1. The ejector cams are mounted on a cam-shaft 65 passing throughthe lower part of the machine frame. The two cropping ejectors are alsoactuated by ejector cams on the shaft 65, but these ejectors and camsare not illustrated in FIG. 1.

FIG. 11 illustrates, in somewhat simplified form, the first stage ofbank A. The ejector EA] includes an ejector pin 66 which is a closesliding fit within the bore of the die DAl. The pin 66 has a flat upperend 67 on which rests the workpiece 68. FIG. 11 shows the position whenthe workpiece 68 has been struck by the tool 69 in the bottom of thetoolholder ram TA1 which has now withdrawn upwards. The ejector pin 66is nearing its uppermost position, and the workpiece 68 is in a verticalposition, resting on the upper end 67 of the pin 66. The workpiece 68remains in this vertical position as the ejector pin 66 completes itsupward travel, completely ejecting the workpiece 68 from the die. Theworkpiece 68 is then grasped by the fingers FAl and transferred to thenext die.

Referring now to FIGS. 1 2 and 3 this multistage forming machine ispowered by an electric motor 71 which is connected by belt drive 72 tothe input of a variable speed device 73 having a speed control knob 74.The output drive from the device 73 is transmitted through belt drive 75to the input of the pneumatically. operated clutch 76. This clutch isconnected by a pneumatic pipe 77 (FIG. 1) through a suitable controlvalve to source of compressed air. The output shaft 78 of the clutchcarries a spur gear 79 in mesh with an idler gear 81 (only part of whichis seen in FIG. 1). The idler gear 81 is in mesh with a large gear wheel82 secured to one end. of the main camshaft 33 outside one end of themachine frame 1l;- The main camshaft 33 runs completely across themachine and extends through the opposite end of the machine frame, whereit carries a spur gear 83 and a bevel gear 84. The spur gear 83 drives,in succession, an idler spur gear 85, spur gear 86 and bevel gear 87secured to the spur gear 86. The

bevel gear 87 meshes with a bevel gear 88 on the top end of a shortvertical layshaft, the bottom end of which carries another bevel gear 89in mesh with a bevel gear 91 mounted on a horizontal shaft. Thishorizontal shaft is connected through suitable gearing to drive the wirefeed deviceand cropping device of bank A at that end of the machine. Thebevel gear 91 is secured to a shaft 92 which extends back across themachine frame to drive, through suitable gearing, the wire feed deviceand cropping device of bank B atthe other end of the machine. v

The bevel gear 84 on the end of the main camshaft 33 is in mesh with abevel gear 93 on the upper end of a long vertical layshaft 94. To thelower end of this layshaft is secured a bevel gear 95 in mesh with abevel gear 96 secured to the ejector camshaft 65. Thus the ejectorcamshaft is driven in synchronism with the main camshaft 33. The'layshaft 94 also carries a bevel gear 96" which is in mesh with a bevelgear 97. This drives, through a suitable right-angle gear box 98 thecamshaft 29 on which are the rotating cams 30A, 308. Thus the fingerclosing camshaft 29 is also driven in synchronism with the main camshaft33. The layshaft 94 also carries an eccentric cam 99 which drives thetransfer slide 16. The left hand end of the transfer slide (as viewed inFIG. 1) is connected, by means of a dog leg bracket 101, with a 'camfollower slide 102 which can reciprocate in a suitable slideway in abracket 103 extending from the left handend of the machine frame. Theupper face of the cam follower slide carries two cam follower rollers104 and 105, the distance between which is a fit on the longest diameterof the eccentric cam 99. As the cam 99 rotates, the transfer slide isdriven backwards and forwards in synchronism with the'rotation ,of thelayshaft 94, i.e. in synchronism with the rotation of the main camshaft33. FIG. 6 shows in solid lines the position of cam 99 and followers104, 105 when the transfer slide 16 is in its most leftward position (asviewed in FIG. I), and shows ih broken lines the positions of thoseparts when the transfer slide is in its most rightward position.

The movements of the two banks of the machine are arranged so that theyare substantially 180 out of phase with each other. This is illustratedby a comparison of FIGS. 7 and 8. FIG. 7 shows the situation in whichthe transfer slide 16 is at the left hand end of its travel, thetoolholders TAl, TAZ, TA3 and TA4, and theejectors EAl, EA2, EA3 andEA4, of the bank A being all in their fully raised position, and thetoolholders T131, T32, T83 and TB4, of bank B all being in their fullylowered positions. FIG. 8 illustrates the position when the maincamshaft has rotated through 180 from the position shown in FIG. 7. InFIG. 8, the transfer slide 16 is at the right hand end of its travel,the

, toolholders and ejectors of bank A are in their fully loweredpositions, and the toolholders and ejectors of bank B are in their fullyraised positions.

The other corresponding working parts of the two banks are alsorespectively 180 out of phase. FIG. 5 illustrates. the way inwhichvarious cams of the two banks respectively are 180 out of phase. InFIG. 5, there are shown in solid lines the position of the main raisingcam RCAl of the first stage of bank A, the ejector cam ECAI of stage 1of bank A and the finger closing cam 30A of stage 1 of bank A. In brokenlines are shown the positions of the corresponding main raising cam RCBlof stage 1 of bank B, the ejector cam ECBl of stage 1 of bank B, and thefinger closing cam 30B of stage 1 of bank B. It will be seen that ineach case, the cam of bank B is 180 out of phase with respect to thecorresponding cam in bank A. It should be noted that FIG. 5 is merelyintended to illustrate this feature, and that the relative angularpositions of the different types of cams, i.e. toolholderraising cam,ejector cam, and fingerclosing cam, of either bank are not necessarilyaccurately shown in FIG. 5.

The multi-stage forming machine described in the, foregoing example isadvantageous in a number of ways. Since the two banks of the machine are180 out of phase, the loads on the camshafts and their associateddriving gear are more evenly distributed than if all the loads weretaken at only one point in the cycle of rotation. The use of a singletransfer slide for both banks of the machine means that the machineoccupies less space than two separate single bank machines. In practice,the double bank machine of the above example occupies aboutthree-quarters of the space which would be occupied by two separatesingle bank machines immediately adjacent each other. This constitutes avaluable saving of floor space in a factory. The fact that a workpiecein the machine is at all stages in a vertical position has the advantagethat the workpiece does not tend to topple sideways or downwards, asoccurs with multi-stage forming machines in which workpieces arehorizontal. Thus the machine of this example is much less prone tojamming than machines with horizontal workpieces. It will also handlemuch shorter blanks and workpieces, since these can be fully ejectedfrom the dies before being gripped by the transfer fingers.

The invention is not restricted to the details of the foregoing example.For instance, instead of the single discharge station for the finishedworkpieces of both banks, it would be possible to provide separatedischarge stations, so that the workpieces produced by one bank arecollected separately from those produced by the other bank. This couldbe achieved on the machine of the above example by providing a movabledeflector plate at the discharge station which moves in synchronism withthe transfer slide to deflect the workpieces from one bank in onedirection and the workpieces from the other bank in another direction.Alternatively, the two banks could be moved slightly apart, so that thedistance between the two last stage dies DA4 and DB4 is more than twicethe distance between one die and the next, thus providing the two spacedapart discharge stations for the two banks. When the workpiecesmanufactured by the two banks respectively are collected separately, thetooling of each bank may be arranged so that the two banks form articlesof different shapes. When this is so, it is desirable that the loads oneach half of the main cam-shaft are kept as near as possible equal toeach other.

Each bank of the machine need not contain four stages, but could containtwo, three, five, six or even more stages. The invention could beapplied to a.

machine with a somewhat different form of transfer mechanism, providedthat the transfer mechanism utilizes a reciprocating transfer slide andthat a common transfer slide is used for the two banks.

We claim: 1. A multi-stage forming machine of the type defined, whichmachine comprises:

first and second banks, each having a plurality of dies, associatedtoolholders, workpiece-gripping means and transfer means; means forreciprocating the toolholders of said first bank substantially 180 outof phase with the toolholders of said second bank; I a reciprocabletransfer slide common to the transfer means of both said banks; thearrangement being such that when the said reciprocable transferslide ismoving in one sense the workpiece-gripping means of the said second bankare returning, and when the said common reciprocable transfer slide ismoving in the opposite sense the workpiece-gripping means of the saidfirst bank are. returning while the workpiecegripping means of thesaid-second bank are advancing;

thesaidcommon reciprocable transfer slide compris-

1. A multi-stage forming machine of the type defined, which machinecomprises: first and second banks, each having a plurality of dies,associated toolholders, workpiece-gripping means and transfer means;means for reciprocating the toolholders of said first bank substantially180* out of phase with the toolholders of said second bank; areciprocable transfer slide common to the transfer means of both saidbanks; the arrangement being such that when the said reciprocabletransfer slide is moving in one sense the workpiece-gripping means ofthe said second bank are returning, and when the said commonreciprocable transfer slide is moving in the opposite sense theworkpiece-gripping means of the said first bank are returning while theworkpiece-gripping means of the said second bank are advancing; the saidcommon reciprocable transfer slide comprising first and second members,said first member associated with the said workpiece-gripping means ofsaid first bank and said second member associated with the saidworkpiece-gripping means of said second bank, said first and secondmembers being linked together for movement in unison by an adjustablelinkage which provides for relative adjustment of said first member andsaid second member in the direction of their reciprocation.